collab: Lay groundwork for reconciling with Stripe using the events API (#15459)

This PR lays the initial groundwork for using the Stripe events API to
reconcile the data in our system with what's in Stripe.

We're using the events API over webhooks so that we don't need to stand
up the associated infrastructure needed to handle webhooks effectively
(namely an asynchronous job queue).

Since we haven't configured the Stripe API keys yet, we won't actually
spawn the reconciliation background task yet, so this is currently a
no-op.

Release Notes:

- N/A

crates/collab/src/db/queries/billing_customers.rs

@@ -39,4 +39,18 @@ impl Database {
         })
         .await
     }
+
+    /// Returns the billing customer for the user with the specified Stripe customer ID.
+    pub async fn get_billing_customer_by_stripe_customer_id(
+        &self,
+        stripe_customer_id: &str,
+    ) -> Result<Option<billing_customer::Model>> {
+        self.transaction(|tx| async move {
+            Ok(billing_customer::Entity::find()
+                .filter(billing_customer::Column::StripeCustomerId.eq(stripe_customer_id))
+                .one(&*tx)
+                .await?)
+        })
+        .await
+    }
 }

crates/collab/src/db/queries/billing_subscriptions.rs

@@ -30,6 +30,31 @@ impl Database {
         .await
     }
 
+    /// Upserts the billing subscription by its Stripe subscription ID.
+    pub async fn upsert_billing_subscription_by_stripe_subscription_id(
+        &self,
+        params: &CreateBillingSubscriptionParams,
+    ) -> Result<()> {
+        self.transaction(|tx| async move {
+            billing_subscription::Entity::insert(billing_subscription::ActiveModel {
+                billing_customer_id: ActiveValue::set(params.billing_customer_id),
+                stripe_subscription_id: ActiveValue::set(params.stripe_subscription_id.clone()),
+                stripe_subscription_status: ActiveValue::set(params.stripe_subscription_status),
+                ..Default::default()
+            })
+            .on_conflict(
+                OnConflict::columns([billing_subscription::Column::StripeSubscriptionId])
+                    .update_columns([billing_subscription::Column::StripeSubscriptionStatus])
+                    .to_owned(),
+            )
+            .exec_with_returning(&*tx)
+            .await?;
+
+            Ok(())
+        })
+        .await
+    }
+
     /// Returns the billing subscription with the specified ID.
     pub async fn get_billing_subscription_by_id(
         &self,

crates/collab/src/db/queries/users.rs

@@ -61,6 +61,17 @@ impl Database {
         .await
     }
 
+    /// Returns a user by email address. There are no access checks here, so this should only be used internally.
+    pub async fn get_user_by_email(&self, email: &str) -> Result<Option<User>> {
+        self.transaction(|tx| async move {
+            Ok(user::Entity::find()
+                .filter(user::Column::EmailAddress.eq(email))
+                .one(&*tx)
+                .await?)
+        })
+        .await
+    }
+
     /// Returns a user by GitHub user ID. There are no access checks here, so this should only be used internally.
     pub async fn get_user_by_github_user_id(&self, github_user_id: i32) -> Result<Option<User>> {
         self.transaction(|tx| async move {